Kitchen Extractor Fan Diagnostic Tool
How is your extractor fan behaving? Select the symptom that best matches what you're experiencing, and we'll diagnose the likely cause and guide you through the fix.
Hums but doesn't spin
You hear a humming noise when you turn it on, but the blades don't move
No power at all
Complete silence—nothing happens when you press the switch
Weak suction
Fan runs but barely pulls air; smoke and smells linger in the kitchen
Loud rattling or grinding
Unusual noises like rattling, grinding, or squealing during operation
Burning smell
You notice a distinct burning odor coming from the unit
Excessive vibration
The whole unit shakes or vibrates noticeably when running
Select a symptom above
Choose the issue you're experiencing to receive a diagnosis and repair guidance
There is nothing quite as frustrating as cooking a big meal only to have the smell of burnt garlic linger in your home for days. You reach up to turn on your kitchen extractor fan, also known as a range hood or ventilation hood, but instead of the reassuring hum of suction, you get silence-or worse, a rattling noise that sounds like loose change in a dryer.
This isn't just an annoyance; it’s a safety hazard. Without proper ventilation, grease builds up on surfaces, fire risks increase, and indoor air quality plummets. If your unit has suddenly quit, don’t panic. Most failures are due to simple, fixable issues rather than catastrophic mechanical failure. Let’s look at why these units fail and how you can get them running again.
The Silent Killer: Grease Buildup
If there is one thing that destroys extractor fans faster than anything else, it is grease. When you cook, especially when frying or searing meat, microscopic oil particles fly into the air. Your fan pulls these particles in, but if the filters aren’t cleaned regularly, that grease coats the internal components.
Grease acts like a heavy blanket over the fan motor. It adds weight to the impeller blades, making them harder to spin. Over time, this extra load causes the motor to overheat and eventually burn out. In my experience repairing hundreds of units in Wellington homes, I find that nearly 40% of "dead" motors were actually just choked by years of neglected filter cleaning.
You should check your grease filters every month. Metal mesh filters can be soaked in hot soapy water or run through the dishwasher. Charcoal filters, however, need replacing every three to six months because they trap odors, not just grease, and cannot be washed.
Electrical Issues: The Power Supply Check
Before you assume the motor is dead, rule out the basics. Is the fan plugged in? It sounds silly, but kitchen appliances often get bumped behind cabinets, loosening plugs. If your unit is hardwired, check your circuit breaker. A tripped breaker might mean an overload elsewhere in the kitchen, such as a toaster or kettle fighting for power.
If the power is on but the fan doesn’t start, the issue might lie with the control switch or wall switch. Switches wear out over time. The internal contacts can corrode or break, preventing electricity from reaching the motor. You can test this with a multimeter to see if voltage is reaching the fan terminals. If voltage is present but the fan remains silent, the problem is inside the unit.
Motor Failure and Capacitor Problems
The heart of any extractor system is the electric motor. Motors in these units are typically small, single-phase induction motors designed for continuous low-speed operation. They are robust, but they do fail. Common signs of motor death include a burning smell, a humming sound without blade movement, or complete silence despite power being supplied.
Often, the culprit isn’t the motor windings themselves but the start capacitor. This small component gives the motor the initial jolt needed to start spinning. If the capacitor fails, the motor will hum but never turn. Replacing a capacitor is a cheap and easy fix compared to buying a new motor. However, if the motor bearings are seized due to lack of lubrication or heat damage, replacement is usually more cost-effective than repair.
Ductwork Blockages and Airflow Resistance
Even if your motor is brand new, your fan won’t work if the air has nowhere to go. Many modern homes use ducted systems that vent outside, while others use recirculating systems with charcoal filters. If you have a ducted system, blockages are a major cause of poor performance.
Birds, squirrels, or even leaves can nest in the external vent cap. Inside the walls, flexible ducting can collapse or kink, restricting airflow. High resistance forces the motor to work harder, leading to premature failure. To check for blockages, remove the outer vent cover and shine a flashlight down the pipe. If you can’t see light coming from the other end, you likely have an obstruction. Use a shop vac on blow mode or a long brush to clear it.
Wiring and Connection Faults
Vibration from the fan blades can loosen wire connections over time. Inside the housing, spade connectors or screw terminals may become loose, causing intermittent operation or total failure. Always disconnect power before opening the unit. Inspect all wiring for frayed insulation, burnt marks, or loose connections. Tighten any loose screws and replace damaged wires immediately to prevent short circuits.
| Symptom | Likely Cause | Recommended Action |
|---|---|---|
| Fan hums but doesn't spin | Bad start capacitor or seized motor | Test/replace capacitor; inspect motor bearings |
| No power, no noise | Tripped breaker, loose plug, or bad switch | Check breaker, plug, and wall switch continuity |
| Weaker suction than usual | Clogged filters or blocked ductwork | Clean metal filters; inspect duct path for obstructions |
| Loud rattling or grinding | Loose blades, foreign object, or worn bearings | Tighten screws; remove debris; consider motor replacement |
| Burning smell | Overheating motor or electrical short | Turn off immediately; inspect wiring and motor condition |
When to Call a Professional
While many issues can be DIY fixes, some situations require expert help. If your unit is hardwired into your home’s electrical system and you’re uncomfortable working with mains voltage, hire an electrician. Similarly, if the motor needs replacement and involves removing the entire hood from the ceiling or wall, professional installation ensures proper sealing and balance. In New Zealand, always ensure repairs comply with local electrical standards (AS/NZS 3000) to maintain insurance validity.
Prevention Tips for Longevity
To avoid future headaches, adopt a simple maintenance routine. Clean filters monthly. Wipe down the interior surface of the hood weekly to catch splatter before it drips into the mechanism. Run the fan for five minutes after cooking to clear residual smoke and grease particles. These small habits can extend the life of your extractor fan by years.
How much does it cost to repair a kitchen extractor fan?
Costs vary widely. Cleaning filters is free if done yourself. Replacing a capacitor costs $10-$30 plus labor if hired. Motor replacements range from $50 to $150 for parts. Full professional service calls in Wellington typically start around $80-$120 for diagnosis plus parts and labor. Always get a quote before authorizing major repairs.
Can I clean the internal fan blades myself?
Yes, but proceed with caution. Unplug the unit first. Remove the front grille and filters. Use a soft brush or vacuum attachment to gently remove grease from the visible blades. Avoid harsh chemicals that could damage plastic components. For deep cleaning, specialized degreasers work well.
Is it worth repairing an old extractor fan?
It depends on age and value. If your unit is less than 10 years old and the repair cost is under half the price of a new model, repair is usually worthwhile. Older units may lack efficiency ratings and safety features found in newer models, making replacement a better long-term investment.
Why does my extractor fan vibrate excessively?
Vibration often stems from unbalanced fan blades, loose mounting screws, or worn motor bearings. Check that all screws securing the housing and internal components are tight. Inspect blades for buildup or damage. If bearings are worn, the motor may need replacement.
Do I need a permit to replace a kitchen extractor fan in New Zealand?
Generally, no permit is needed for like-for-like replacement of existing fixtures. However, if you’re changing the electrical circuit location or adding new ductwork through exterior walls, check with your local council. Electrical work must still comply with AS/NZS 3000 standards and ideally be certified by a licensed electrician.